--- libexec/ftpd/extern.h.orig	2015-03-10 20:41:45.000000000 +0700
+++ libexec/ftpd/extern.h	2015-03-10 20:41:56.000000000 +0700
@@ -80,6 +80,7 @@ extern	int epsvall;
 extern	int form;
 extern	int ftpdebug;
 extern	int guest;
+extern	int do_iac;
 extern	union sockunion his_addr;
 extern	char *homedir;
 extern	int hostinfo;
--- libexec/ftpd/ftpcmd.y.orig	2015-03-10 20:41:45.000000000 +0700
+++ libexec/ftpd/ftpcmd.y	2015-03-10 20:41:56.000000000 +0700
@@ -1191,7 +1191,7 @@ getline(char *s, int n, FILE *iop)
 	sigprocmask(SIG_BLOCK, &sset, &osset);
 	while ((c = getc(iop)) != EOF) {
 		c &= 0377;
-		if (c == IAC) {
+		if (do_iac && c == IAC) {
 			if ((c = getc(iop)) == EOF)
 				goto got_eof;
 			c &= 0377;
--- libexec/ftpd/ftpd.c.orig	2015-03-10 20:41:45.000000000 +0700
+++ libexec/ftpd/ftpd.c	2015-03-10 20:45:23.000000000 +0700
@@ -127,6 +127,7 @@ int	paranoid = 1;	  /* be extra careful 
 int	anon_only = 0;    /* Only anonymous ftp allowed */
 int	assumeutf8 = 0;   /* Assume that server file names are in UTF-8 */
 int	guest;
+int	do_iac;
 int	dochroot;
 char	*chrootdir;
 int	dowtmp = 1;
@@ -1014,6 +1015,7 @@ user(char *name)
 	}
 
 	guest = 0;
+	do_iac = 1;
 #ifdef VIRTUAL_HOSTING
 	pw = sgetpwnam(thishost->anonuser);
 #else
@@ -1203,6 +1205,7 @@ end_login(void)
 #endif
 	logged_in = 0;
 	guest = 0;
+	do_iac = 1;
 	dochroot = 0;
 }
 
@@ -1459,6 +1462,7 @@ skip:
 			pw = NULL;
 			return;
 		}
+ 		do_iac = !login_getcapbool(lc, "noiac", 1);
 	}
 	setusercontext(lc, pw, 0,
 		LOGIN_SETLOGIN|LOGIN_SETGROUP|LOGIN_SETPRIORITY|